Kentucky Bluegrass Growth and Water Use Under Different Soil Compaction and Irrigation Regimes1
- K. J. O'Neil and
- R. N. Carrow2
Soil compaction and efficient use of irrigation water are important concerns of turfgrass managers. This field study examined effects of soil compaction on growth and water utilization of a cool-season turfgrass species under different irrigation programs.
A 2-year-old stand of Poa pratensis L., ‘Baron,‘ on a fine, montmorillonitic mesic Aquic Arguidoll soil, was subjected to four treatments resulting from a factorial design with two levels of compaction (none and 30 passes per week with roller) and two levels of irrigation (set schedule of 3.8 cm water per week plus rainfall and 3.8 cm when tensiometer at 10 cm depth read −0.70 bar).
Soil compaction had no effect on root weight or distribution. Visual quality, shoot density, verdure, and percent total cover were reduced by compaction while total nonstructural carbohydrates (TNC) were unaffected. In the surface 3 cm of soil, compaction increased bulk density and moisture retention but reduced aeration porosity at −0.1 bar from 18.1 to 12.5%. Irrigation treatment had no effect on any of the soil physical properties.
Without affecting turf quality, water use with tensiometer was reduced by 28 and 48% on noncompacted and compacted areas, respectively, compared to set-schedule irrigated plots. Water use over a 9-day period in August indicated that the turf grown under the tensiometer scheduled regime was physiologically or anatomically adapted to use less water even when it was available. This adaptation was not due to differences in vegetative or root growth in this study.
Compaction reduced water use by 20% over the 4 month study. During a 9-day period in August, compaction reduced water use by 3.5 to 11% for the tensiometer and set-scheduled treatments, respectively. This response appeared to be due primarily to altered moisture retention properties and reduced shoot growth. Thus, compacted and noncompacted sites should be irrigated on separate schedules.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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